On 02/20/2018 05:26 PM, Martin Liška wrote:
> On 02/20/2018 05:19 PM, Richard Sandiford wrote:
>> Jakub Jelinek <ja...@redhat.com> writes:
>>> On Tue, Feb 20, 2018 at 03:58:07PM +0000, Richard Sandiford wrote:
>>>> Martin Liška <mli...@suse.cz> writes:
>>>>> Hi.
>>>>>
>>>>> Following patch adds "native" as a possible option for -march value on
>>>>> i386 target. I have similar patches for other targets. Would it be
>>>>> possible to install the patch in current stage?
>>>>
>>>> [...]
>>>>
>>>>> diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
>>>>> index d54e7301e84..361d4df2663 100644
>>>>> --- a/gcc/config/i386/i386.c
>>>>> +++ b/gcc/config/i386/i386.c
>>>>> @@ -4193,6 +4193,9 @@ ix86_option_override_internal (bool main_args_p,
>>>>> || ((processor_alias_table[i].flags & PTA_64BIT) != 0)))
>>>>> candidates.safe_push (processor_alias_table[i].name);
>>>>>
>>>>> + /* Add also "native" as possible value. */
>>>>> + candidates.safe_push ("native");
>>>>> +
>>>>> char *s;
>>>>> const char *hint
>>>>> = candidates_list_and_hint (opts->x_ix86_arch_string, s, candidates);
>>>>
>>>> We should probably only do this if the driver supports -march=native.
>>>> I think for x86 that means HAVE_LOCAL_CPU_DETECT.
>>>
>>> Isn't the option available always? It just doesn't do anything if
>>> /* If we are compiling with GCC where %EBX register is fixed, then the
>>> driver will just ignore -march and -mtune "native" target and will leave
>>> to the newly built compiler to generate code for its default target. */
>>
>> It's only available for x86 hosts:
>>
>> /* -march=native handling only makes sense with compiler running on
>> an x86 or x86_64 chip. If changing this condition, also change
>> the condition in driver-i386.c. */
>> #if defined(__i386__) || defined(__x86_64__)
>> /* In driver-i386.c. */
>> extern const char *host_detect_local_cpu (int argc, const char **argv);
>> #define EXTRA_SPEC_FUNCTIONS \
>> { "local_cpu_detect", host_detect_local_cpu },
>> #define HAVE_LOCAL_CPU_DETECT
>> #endif
>>
>> Non-native hosts are obviously a niche case for x86, but it still
>> seems better to be consistent.
>>
>> Richard
>>
>
> So would it enough to wrap 'candidates.safe_push ("native");' by
> #ifdef HAVE_LOCAL_CPU_DETECT
> ?
>
> Thanks,
> Martin
>
There's updated version of the patch I've just tested.
Martin
>From 8f1783a9017ec06c578fd644e46168ec5763d5ca Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Tue, 20 Feb 2018 14:21:05 +0100
Subject: [PATCH 3/3] Add "native" as a valid option value for -march= on i386
(PR driver/83193).
gcc/ChangeLog:
2018-02-20 Martin Liska <mli...@suse.cz>
PR driver/83193
* config/i386/i386.c (ix86_option_override_internal):
Add "native" as a possible value.
---
gcc/config/i386/i386.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index d54e7301e84..9f2c5218ae5 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -4193,6 +4193,11 @@ ix86_option_override_internal (bool main_args_p,
|| ((processor_alias_table[i].flags & PTA_64BIT) != 0)))
candidates.safe_push (processor_alias_table[i].name);
+#ifdef HAVE_LOCAL_CPU_DETECT
+ /* Add also "native" as possible value. */
+ candidates.safe_push ("native");
+#endif
+
char *s;
const char *hint
= candidates_list_and_hint (opts->x_ix86_arch_string, s, candidates);
--
2.16.1
